Study On Preparation And Properties Of P-SrCu₂O₂ Transparent Conductive Oxides Films

The delafossite structure, p-type and directly band-gap electrical conductivity transparent oxide thin film of SrCu2O2 was designed by A.kudo in 1998 for the first time. Based on p-SrCu2O2 and n-ZnO films, hetero-junctions transparent near-UV LEDS have been successfully developed. SrCu2O2 has become the hot spot of the area of transparent and conductivity film.In this paper, high quality SCO thin films were prepared by direct current (DC) reactive magnetron sputtering method using Ca0.1Sr0.9Cu2O2 target synthesized by sintering. XRD,SEM,EDS were used to analyze the surface morphology and structure of target and films. The optical and electrical properties of the SCO thin film prepared in different preparing conditions were analyzed by Hall testing apparatus and double-light ultraviolet and visible photometer.Analysis results of target show that the surface of the target is smooth, and distribution of elements is much more even. Analysis results of thin films show that the structure of thin films is polycrystalline and consists of SCO phase. Crystalline size is 100nm. The surfaces morphology of the films is smooth. Ca,Sr,Cu,O,C are included in SCO thin film and Ca has been successfully doped into SCO thin film.Crystallinity of thin films is improved by annealing.The spectral analysis results indicate that the transmission rate of the thin film is 70%, The transmission rate decreases with the substrate temperature and oxygen argon ratio increasing. The transmission rate will increase if rising the work pressure and distance of target. Along with the annealing temperature increasing, the transmission rate of the thin film also increases.The results of the electrical properties indicate that the conduction of thin film is p-type and annealing and oxygen argon ratio have strong influence the properties of SCO films. The resistivity of the SCO films decreases after annealing, but the carrier concentration and mobility increases. The resistivity decreases while the carrier concentration and mobility increases as decreasing the oxygen argon ratio.Based on the studied of the structural, optical and electrical properties of SCO thin films, it can be obtained the optimal deposition conditions of SCO thin films by direct current reactive magnetron sputtering. The oxygen argon ratio, deposition temperature, gas pressure, distance of target and substrate, sputtering power and annealing temperature are 12/24,200℃,5.0Pa,7.0cm, 36W,800℃, respectively. In this condition, The resistivity and carrier concentration of thin film are 21.2Ω·cm, 4.073×1016cm-3 respectively, and the transmission rate of the thin film is above 70%.